1. Field of the Invention
The present invention relates to a field of ion drift technology, and in particular to an electrode structure for an ion drift tube and an ion drift tube including the same.
2. Description of the Related Art
In the field of safety inspection, detection of hazardous articles such as drugs, explosives, chemical agents and industrial toxicants is an extremely important work. Therefore, many detection instruments for the above articles have been developed. Currently, the detection instruments using the ion drift technology are most common. Two indexes that are most crucial in the ion drift technology are sensitivity and resolution of a detector. It is a main object of design and fabrication of the ion drift tube to optimize the two indexes. The ion drift tube is a core part of an ion mobility spectrometer and is used to generate a uniform electric field so that ions having different mobilities are separated. As shown in FIG. 1, in a conventional ion drift tube, drift of ions is controlled by a uniform high-voltage electric field by thin sheet electrodes 1 having the same size spaced equidistantly by means of insulating parts 3. In the ion drift tube, the ions drift in the air under the normal pressure. The uniform electric field generated by the conventional structure shown in FIG. 1 is an approximate model and a non-ideal uniform electric field. In addition, the ions are simultaneously subjected to factors such as the high-voltage electric field and air resistance. Therefore, uniform equidistant high-voltages cannot well generate pre-acceleration, focusing, a maximal amount of drift of the ions and the like. As a result, it is difficult for sensitivity and resolution of a mobility spectrum obtained by the ion mobility spectrometer to reach optimum.